Brian O'Driscoll has opened up on the use of legal painkillers in rugby, and says that towards the end of his career he would have taken them before games 'like habit'.

Many painkillers are perfectly legal for rugby players to use before games and do not require Therapeutic Use Exemptions (TUEs), which are needed for some stronger painkillers.

The use of painkillers in rugby has been heavily debated in recent times, with Sunday Independent journalist Paul Kimmage arguing that professional players are endangering their health by relying on them to get through matches.

Speaking on Off The Ball on Newstalk, O'Driscoll said that he used to routinely take Difene before games and did so to help his body get close to 100% so that he could compete.

"I would have been part of teams where on the way to games, a doctor would have walked down the bus and asked who wanted what in advance of it," O'Driscoll said.

"For me, for the last couple of seasons, it would have been part of my match prep."

"It almost became like habit," he added.

"It gave me a fighting chance, if I wasn't feeling 100%, that it might have levelled it up. I wouldn't have been the only one. It was mostly the older players, trying to balance the equilibrium almost.

"I'm sure at times, in my subconscious, I would have just taken it because it became part and parcel, when maybe I could have done without it.

"Again, when it's perfectly legal and there are no need for TUEs, give yourself a chance to play your best game."